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Observation of prethermalization in long-range interacting spin chains
Brian Neyenhuis1, Jiehang Zhang1, Paul W Hess1
1Joint Quantum Institute and Joint Center for Quantum Information and Computer Science, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, MD 20742, USA.
Science Advances
|September 7, 2017
Summary
Quantum systems can enter prethermal states, not always reaching full thermal equilibrium. Long-range interactions lead to unique prethermal states that defy standard descriptions, challenging thermalization theories.
Area of Science:
- Quantum Many-Body Physics
- Statistical Mechanics
- Quantum Information
Background:
- Statistical mechanics typically describes thermal equilibrium states.
- Quantum systems near integrability often fail to thermalize rapidly, instead reaching prethermal states.
- Prethermal states can be described by generalized Gibbs ensembles (GGE) when conserved quantities exist.
Purpose of the Study:
- To experimentally investigate the relaxation dynamics of a quantum spin chain after a sudden quench.
- To explore prethermalization in systems with long-range interactions.
- To determine if standard GGE can describe these novel prethermal states.
Main Methods:
- Experimental study of a 22-spin chain using a long-range transverse-field Ising Hamiltonian.
- Sudden quench protocol to initiate dynamics.
- Analysis of relaxation dynamics and prethermal state properties.
Main Results:
- For long-range interactions, the system relaxes to a prethermal state retaining memory of initial conditions.
- This novel prethermal state cannot be described by a standard GGE.
- An emergent double-well potential for spin excitations governs this prethermal state.
Conclusions:
- Prethermalization occurs in a broader range of quantum systems than previously understood.
- Long-range interactions introduce unique prethermal phenomena not captured by standard GGE.
- Understanding thermalization in quantum systems with long-range interactions requires new theoretical frameworks.
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